`delete.intercept` <-
function (mm){
      saveattr <- attributes(mm)
      intercept <- which(saveattr$assign == 0)
      if (!length(intercept))
        return(mm)
      mm <- mm[, -intercept, drop = FALSE]
      saveattr$dim <- dim(mm)
      saveattr$dimnames <- dimnames(mm)
      saveattr$assign <- saveattr$assign[-intercept]
      attributes(mm) <- saveattr
      mm
    }
